package com.sakura.util.CAS;

/**
 * Created by apple on 2018/8/2.
 */

import java.util.Random;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.locks.ReentrantLock;

import static java.lang.System.out;

public class TestSyncMethods {

    public static void test(int round,int threadNum,CyclicBarrier cyclicBarrier){
        new SyncTest("Sync",round,threadNum,cyclicBarrier).testTime();
        new LockTest("Lock",round,threadNum,cyclicBarrier).testTime();
        new AtomicTest("Atom",round,threadNum,cyclicBarrier).testTime();
    }

    public static void main(String args[]){

        for(int i=0;i<5;i++){
            int round=100000*(i+1);
            int threadNum=5*(i+1);
            CyclicBarrier cb=new CyclicBarrier(threadNum*2+1);
            out.println("==========================");
            out.println("round:"+round+" thread:"+threadNum);
            test(round,threadNum,cb);

        }
    }
}

class SyncTest extends TestTemplate{
    public SyncTest(String _id,int _round,int _threadNum,CyclicBarrier _cb){
        super( _id, _round, _threadNum, _cb);
    }
    @Override
    /**
     * synchronized关键字不在方法签名里面，所以不涉及重载问题
     */
    synchronized long  getValue() {
        return super.countValue;
    }
    @Override
    synchronized void  sumValue() {
        super.countValue+=preInit[index++%round];
    }
}


class LockTest extends TestTemplate{
    ReentrantLock lock=new ReentrantLock();
    public LockTest(String _id,int _round,int _threadNum,CyclicBarrier _cb){
        super( _id, _round, _threadNum, _cb);
    }
    /**
     * synchronized关键字不在方法签名里面，所以不涉及重载问题
     */
    @Override
    long getValue() {
        try{
            lock.lock();
            return super.countValue;
        }finally{
            lock.unlock();
        }
    }
    @Override
    void sumValue() {
        try{
            lock.lock();
            super.countValue+=preInit[index++%round];
        }finally{
            lock.unlock();
        }
    }
}


class AtomicTest extends TestTemplate{
    public AtomicTest(String _id,int _round,int _threadNum,CyclicBarrier _cb){
        super( _id, _round, _threadNum, _cb);
    }
    @Override
    /**
     * synchronized关键字不在方法签名里面，所以不涉及重载问题
     */
    long  getValue() {
        return super.countValueAtmoic.get();
    }
    @Override
    void  sumValue() {
        super.countValueAtmoic.addAndGet(super.preInit[indexAtomic.get()%round]);
    }
}
abstract class TestTemplate{
    private String id;
    protected int round;
    private int threadNum;
    protected long countValue;
    protected AtomicLong countValueAtmoic=new AtomicLong(0);
    protected int[] preInit;
    protected int index;
    protected AtomicInteger indexAtomic=new AtomicInteger(0);
    Random r=new Random(47);
    //任务栅栏，同批任务，先到达wait的任务挂起，一直等到全部任务到达制定的wait地点后，才能全部唤醒，继续执行
    private CyclicBarrier cb;
    public TestTemplate(String _id,int _round,int _threadNum,CyclicBarrier _cb){
        this.id=_id;
        this.round=_round;
        this.threadNum=_threadNum;
        cb=_cb;
        preInit=new int[round];
        for(int i=0;i<preInit.length;i++){
            preInit[i]=r.nextInt(100);
        }
    }

    abstract void sumValue();
    /*
     * 对long的操作是非原子的，原子操作只针对32位
     * long是64位，底层操作的时候分2个32位读写，因此不是线程安全
     */
    abstract long getValue();

    public void testTime(){
        ExecutorService se=Executors.newCachedThreadPool();
        long start=System.nanoTime();
        //同时开启2*ThreadNum个数的读写线程
        for(int i=0;i<threadNum;i++){
            se.execute(new Runnable(){
                public void run() {
                    for(int i=0;i<round;i++){
                        sumValue();
                    }

                    //每个线程执行完同步方法后就等待
                    try {
                        cb.await();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (BrokenBarrierException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }


                }
            });
            se.execute(new Runnable(){
                public void run() {

                    getValue();
                    try {
                        //每个线程执行完同步方法后就等待
                        cb.await();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (BrokenBarrierException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                }
            });
        }

        try {
            //当前统计线程也wait,所以CyclicBarrier的初始值是threadNum*2+1
            cb.await();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (BrokenBarrierException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        //所有线程执行完成之后，才会跑到这一步
        long duration=System.nanoTime()-start;
        out.println(id+" = "+duration);

    }

}


